AMI system for performing phase detection and synchronization in AMI communication network using relay communication method, and method thereof

Abstract

The present invention relates to a system for performing phase detection and synchronization in an AMI communication network using a relay communication, and a method thereof. According to an embodiment of the present invention, a system for performing phase detection and synchronization in an AMI communication network using a relay communication includes an AMI server for collecting a ‘reference zero-crossing detection (ZCD) time difference by phase’ of input/output terminals of a main transformer installed in a substation; and a data concentration unit (DCU) comparing the ‘reference ZCD time difference by phase’ transmitted from the AMI server with a ‘ZCD time difference by phase’ collected by itself, and matching the same to have a time difference close to an error range.

The invention claimed is: 
     
       1. An AMI system of performing phase detection and synchronization in an AMI communication network, the system comprising:
 an AMI server collecting a “reference zero-crossing detection (ZCD) time difference by phase” of input/output terminals of a main transformer installed in a substation; and 
 a data concentration unit (DCU) comparing the “reference ZCD time difference by phase” transmitted from the AMI server with a “ZCD time difference by phase” collected by itself, and matching the ZCD time difference by phase with the reference ZCD time difference by phase to have a time difference close to an error range. 
 
     
     
       2. The AMI system of  claim 1 , wherein the ZCD time difference is determined by counting an interval between a “GPS PPS signal” that becomes a pulse counting basis, and a “ZCD pulse” as clock pulses. 
     
     
       3. The AMI system of  claim 1 , wherein the DCU includes:
 an oscillator unit generating a clock pulse; 
 a GPS receiver unit determining a GPS pulse per second (PPS) signal from a received GPS signal; 
 a ZCD circuit unit connected to a secondary side of a pole transformer, and determining a ZCD pulse by phase; and 
 a pulse counting unit determining a ZCD time difference by phases by counting an interval between the GPS PPS signal and the ZCD pulse by phase as clock pulses. 
 
     
     
       4. The AMI system of  claim 1 , wherein the AMI server collects the “ZCD time difference by phase” by using a reference phase detection unit connected to the input/output terminals of the main transformer installed in the substation. 
     
     
       5. The AMI system of  claim 1 , wherein the DCU determines a phase of a master modem in a relay communication by using a ZCD time difference between phases on the basis of a ZCD point of a specific phase, and then determines a phase of a slave modem. 
     
     
       6. The AMI system of  claim 5 , wherein the DCU determines the phase of the master modem which directly performs communication without using a relay modem, and determines phase information of the slave modem by using “phase information of the master modem” and a time difference calculated from a phase detection packet transmitted from the slave modem by the master modem. 
     
     
       7. The AMI system of  claim 1 , wherein the DCU detects a phase of a modem by accumulating in manner that a ZCD signal is transmitted in a relay communication by using a ZCD time difference between phases on the basis of a ZCD point of a specific phase. 
     
     
       8. The AMI system of  claim 7 , wherein the modem transmits an accumulated ZCD signal time difference of a previous section which is a result obtained by adding a ZCD signal time difference obtained by itself and a ZCD signal time difference of a slave modem. 
     
     
       9. The AMI system of  claim 7 , wherein the DCU determines phase information of a termination modem by performing remainder arithmetic operation (MOD operation) that divides the accumulated ZCD signal time difference of the previous section transmitted from the modem by a total number of phases. 
     
     
       10. A method of performing phase detection and synchronization in an AMI communication network, the method comprising:
 collecting, by an AMI server, a “ZCD time difference by phase” of input/output terminals of a main transformer installed in a substation; 
 collecting, by a DCU, a “ZCD time difference by phase” of the same timing as the ZCD time difference by phase of the input/output terminals; and 
 comparing, by the DCU, the “ZCD time difference by phase” transmitted from the AMI server with the “ZCD time difference by phase” collected by itself, and matching the ZCD time difference by phase collected by itself with the transmitted ZCD time difference by phase to have a time difference close to an error range. 
 
     
     
       11. The method of  claim 10 , wherein further comprising:
 after the performing of the matching, 
 determining, by the DCU, phase information of a master modem that is directly connected thereto without using a relay modem; and 
 determining, by the DCU, phase information of a slave modem by using the “phase information of the master modem” and a time difference calculated from a phase detection packet transmitted from a slave modem by the master modem. 
 
     
     
       12. The method of  claim 10 , wherein further comprising:
 after the performing of the matching, 
 transmitting, by a modem, to a subsequent master modem an accumulated ZCD signal time difference of a previous section which is a result obtained by adding own ZCD signal time difference and a ZCD signal time difference of a slave modem; and 
 determining, by the DCU, phase information of a termination modem by using the accumulated ZCD signal time difference of the previous section. 
 
     
     
       13. The method of  claim 10 , wherein the ZCD time difference is determined by counting an interval between a “GPS PPS signal” that becomes a pulse counting basis and a “ZCD pulse” as clock pulses.